Heating apparatus



May 14, 1940. J. c. wooDsoN HEATING APPARATUS Filed Nov. l5, 1938 lNvENToR 4,0 ing elements according to my invention installed l and the Work traversing the Conveyor 40 den@ May '14, 1940 2,200,731

UNITED lsimiazs 'P .Afrrziu OFFICE HEATING APPARATUS 4 James C. Woodson, Cleveland, Ohio, assigner to Lee Wilson Sales Corporation, Cleveland, Ohio,

a corporation of Ohio Application November 15, 1938, Serial No. 240,497

6 Claims. (Cl. 126-91) This invention relates generally to heating The furnace I0 may be of any desired type but and, particularly, to a heating element of that is herein illustrated as of the continuous tunnel type known as radiant tube heaters. type, being provided with a roller conveyor or Various types of radiant' tube heaters have hearth composed of a plurality of conveyor rollbeen employed in numerous applications. The ers I 6 journaled in suitable bearings I'l carried 5 heating element of my invention is an improve- 0n the furnace frame, and driven by any suitable ment over those previously known in respect to means such as a chain and sprocket drive indithermal efficiency and simplicity of structure. cated at I8.

It is intended particularly for heating by the Heating elements i9 embodying my invention 10 combustion of fuel ali-relatively low pressure. may Conveniently be mounted above 0r below 10 As will be apparent from the following detailed the Conveyor roller l@ or both and, if the latter description, the invention provides a heating eleare ,preferably staggered above and below the ment applicable to a' wide variety of uses and the Conveyor rollers. As shown, each heating ele- .application thereofv disclosed herein is, therement comprises a tubular Shell or body portion M fore, to beconsidered purely illustrative. u 2o having generally the Shape of a flattened 15 Briefly stated, the heating element of my inbottle witha neck 2l of reduced cross section Vention comprises a tubular sh'ell 01' bgdy p01'- eXtending from One end, thereof through One Of tion having a neck, preferably of reduced cross the Side Walls of the llrnaoe- The opposite end section, extending from one end thereof. l proof the tubular shell is closed by a cover 2t'. The A vide` means such as a transverse baflle extending Cover 2li' has a foot 22 thereon adapted to rest 2@ along `the tubular shell to divide it into outward on a shoulder 23 formed in one of the side Walls and return combustion passages communicating 0f the furnace t0 lreceive it.- l with .the neck. An inlet, pip-e for supplying g, The tubular shell 26, as shown in Fig. 3, is of combustible mixture to the outward combustion Substantially oval Seetion and the Side Walls passage extends into the latter through the neck. thereof are Provided With spaced inwardly 9X' 25 The result of this construction is that after tending ribs or guides 24- Refractory blocks or traversing the length oi the shell twice, i. e., Slabs 25 are inserted in tlle guides 24 by Slidingonce in each direction, the combustion gases are them inwardly thereelong While the Col/'er 20' discharged through the neck in close proximity iS removed! InWardlY extending lngS 26 0n the 30 to the entering components of the combustible cc"Ver hold the blocks 25 in Ploe When the Cover 30 mixture, whereby the latter are pre-heated. is positioned on the Shell Further details of the construction and opera- The blocks 25 forme transverse baille extend' tion will be explained hereinafter with reference ing along the body portion 2@ 0f the Shell, deto the accompanying drawing illustrating. a prelining entering and return Passages 27 and 2li fen-ed embodiment and practicerespectively, on opposite sides thereof. By estab- In the drawing: l lishinga flow of combustible gases through the Fig. l is a transverse sectional view through a l passages 27 and 23 the Shell 20 iS heated by the more or less conventional tunnel type or con- Combustion thereof t0 a' temperature at Which gygy hearth furnace Showing, in elevation, heat.. radiates t0 the interior Of the furnace therein; rollers I6. i 'in Fig. 2 is a transverse sectional view through I supply a combustible mixture to the outone of the heating elements taken substantially Ward passage 2 through an inlet pipe 29 eX- along the'plane of line Il-II of Fig. l;V tending through a 4suitable opening in a cover Fig. 3 is a sectional View through the heating plate 30 secured to the end of the neck portion 45 element and furnace. taken substantially along 2l of the heating element. Airfor combustion is the plane indicated by line IIL-III of Fig. 2, withV supplied t0 the pipe 29 from 2 Dine 3|- The pipe parts in elevation; and i 3| is threaded into a T 32 connected to the pipe Fig. 4 is a section along the same plane as 29 by a nipple 33 and a flanged sleeve 34, and

Fig. 3, showing a portion illustrated in elevation is connected to any suitable Source of air under 5o in the latter to enlarged scale. relatively low pressure, such as a blower. Fluid Referring now in detail to the drawing, a fur fuel from any convenient source, preferably A nace IU `comprises side walls `I I, a oor I2, and under low pressure, is supplied to the pipe 29 a roof I3 assembled Within a structural frame by a pipe 35 having an elbow 36 threaded into 66 including buckstays I4 and sheathing plates I5. a plug 31 in one end of the T 32. A fuel pipe 38 55 is threaded into Ythe plug 31 and extends along the axis of the pipe 29. 4As shown in Fig. 4, the

furnace end of the pipe 39 is closed but is provided with holes 39. A fuel nozzle 40 is mounted on the end `cf the pipe 38 by an expandercoupling 4|.

As will doubtless be apparent from the firegoing description, when air is supplied to the pipe 29 from the pipe 3| and fuel from the pipe 35 to the nozzle 40 through the pipe 39, Ia combustible mixture will issue from the furnace end passages 21 and 23. This results in a small portion of the combustion products being injected into the stream of combustion gases by thev jet issuing from the pipe 29. Thus, a portion of the combustion products is re-circulated withv the fresh combustible mixture during combustion of the latter as it progresses through the passages 21 and 28.

The combustion gases discharged through the neck 2| are obviously brought into intimate Icontact with the pipe 29, thereby serving to preheat the air flowing through -the latter toward the discharge end thereof for mixture with the fluid fuel issuing from thev nozzle I0. The .eilect of this pre-heating, obviously, is to increase both the thermal efliciency of the entire heating element and the extent of combustion of the fuel supplied thereto.

It will be apparent from the foregoing de-4 scription. and explanation that the invention provides a heating element vof the radiant tube type which is very simple in construction and highly eficient in operation, thusmaking it possible to construct and operate it at relatively small expense. The structure of the heating element, furthermore, is such as to adapt it forA mounting in a. variety of positions and locations. to suit the requirements of almost any installation. e

, The shell 29 and other metallic portions of l the element subjected to high temperatures are preferably composed of heat-resistant alloy.

f Although I have illustrated and described but a preferred embodiment and practice of the invention, it will be evident that changes in the construction and operation disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim: 1.- A radiant heating element comprising a tubular body portion having a transverse bale therein terminating short of both ends of said portion and dividing it into entering and return. passages for combustion gases, said element also having aY neck portion substantially smaller in sectional area than the body portion and ex-- tending from one end of the latter substantially in alinement with said entering passage, a combustible-mixture supply pipe smaller in sectional area than said neck portion and extending through the latter, and a stack -communicating with the space between said tube and said neck portion.

2. A maiala heating dement as denned in claim 1 characterized by the end of said tubular A body portion remote from the neck portion having generally the shapeofv a spherical segment.

3. A radiant heating element as defined in claim 1 characterized by said baille comprising refractory slabs supported on ribs projecting inwardly from the inner surfaces of said tubular body portion.

4. A radiant heating element as dened in claim 1 characterizedby a-clear space' between 'claim 1 characterized by said tubular body porthe inner end of said tube and the walls dening said enteringpassage, .to permit recirculation ofA part of the combustion gases.

6 A radiant heating element comprising a tubular body portion having a transverse baille therein terminating short of `both ends of said portion and dividing it into entering and return passages for combustion gases, said element also havingv aneck portion substantially smaller in sectional area than the body portion and extending from one end of the latter, a combustibia-mixture supply pipe smaller in lsectional area than said neck portionl and extending 'through the latter, and a stack communicating with ,the space. between said tube and vsaid neck portion. l

' JAMES C. 

